The present invention relates to a guiding catheter which is specifically designed to facilitate the maneuvering of a balloon dilatation catheter or other type catheter into a left main coronary artery. Previous catheters used for this purpose include the Judkins-type catheter.
The present invention recognizes that the problem of backup support must be solved by making a fundamental change in the overall shape/configuration of guiding catheters used for left main coronary arteries. This results in a simple guide catheter that is practical in use without the need for complex or bulky adaptations (additional stiffening means, locking devices, or bracing means) to augment the basic guide catheter. In particular, instead of attempting to increase the stiffness of the distal end portion of the Judkins guide catheter or providing a xe2x80x9clockingxe2x80x9d or xe2x80x9cbracingxe2x80x9d mechanism to prevent prolapse of the guide catheter, the present invention makes a significant change in the overall shape/configuration of a guide catheter in several ways.
The uniqueness of the guide catheter of the present invention results from having analyzed the factors that determine optimal support of a guide catheter within an aortic root complex and arranging these factors in a way to maximize backup support for distal advancement of a balloon catheter through the guide catheter of the present invention. The factors determining the support provided by the guide catheter include the following. First, coaxial intubation of a distal tip of the guide catheter within the ostium of the left main coronary artery. Second, the lack of steep bends or acute angles throughout the length of the guide catheter when deployed in the cardiovascular system. Third, a point of support of the guide catheter against the wall of the ascending aorta that is directly across from the ostium of the left main coronary artery. Fourth, a large supportive segment of the guide catheter that rests against the wall of the ascending aorta to increase stability of the guide catheter within the aortic complex. Fifth, providing a substantially rectilinear axis of support between the ostium of the left main coronary artery and the point of support against the wall of the ascending aorta. Sixth, providing a straight portion which extends proximally from and at a substantial angle relative to the proximal end of the supportive segment that contacts the aortic wall. Providing a configuration of a guide catheter, such as the present invention, which focuses on combining all of these factors to provide an optimal guide catheter results in a guide catheter that functions appreciatively better than the Judkins guide catheter or previous catheters used for angioplasty catheterization of the left main coronary artery. Although several previous catheters have been discussed, none of these are manufactured or provided on a large scale (other than the Judkins guide catheter) and are not used commonly because they are not practical in use and/or do not sufficiently improve the performance of the basic shape of the Judkins guide catheter from which they are adapted.
An angioplasty guide catheter of the present invention is adapted for use with a left main coronary artery within a cardiovascular system. The guide catheter has a distal end portion such that with a distal tip of the distal end portion coaxially intubated within an ostium of the left main coronary artery (i.e., fully disposed within the cardiovascular system), a portion of the distal end portion contacts and rests against and is substantially contiguous with a wall of the ascending aorta and a distal end of the contact portion is substantially directly opposite the ostium of the left main coronary artery. In addition, a portion of the distal end portion of the guide catheter defines a generally rectilinear axis of support extending from the distal end of the contact portion across the ascending aorta to the ostium of the left main coronary artery.
The guide catheter of the present invention in a relaxed state prior to insertion within the cardiovascular has a configuration that causes the advantageous orientation of the guide catheter in the aortic complex. The guide catheter in its relaxed state includes a first straight portion and a distal end portion. The distal end portion includes a second straight portion extending distally from the first straight portion. A first (or tertiary) curve portion of the catheter is defined by the junction of the first straight portion and the second straight portion and forms a mild obtuse angle of between 130xc2x0 to 150xc2x0. A second (or secondary) curve portion extends distally from the second straight portion and has an overall curvature with an arc of about 150xc2x0 to 180xc2x0 and includes at least one curvaceous segments. A third straight portion of the guide catheter extends distally from the secondary curve portion. The arc of the second curve portion is oriented to generally face the interior of the first curve portion. Accordingly, when the second curve portion has an 180xc2x0 arc, the second straight segment is substantially parallel to the third straight segment. A fourth straight portion of the guide catheter extends distally from the third straight portion to define a primary curve portion of the catheter having an obtuse angel of between 140xc2x0 to 160xc2x0.
The guide catheters of the present invention, yield many advantages over previous prior art guide catheters (such as the Judkins-style guiding catheter). These guide catheters of the present invention have an overall configuration or basic shape that is substantially different than a Judkins-style guide catheter. Accordingly, when the guide catheters of the present invention are deployed in the cardiovascular system, an orientation is achieved within the ascending aorta and ostium of the left main coronary artery that is superior (i.e., better) to the corresponding orientation achieved by a Judkins-style guide catheter.
The primary feature of superior (i.e., better) orientation of the guide catheters of the present invention is that, when disposed in the aortic complex, a contact portion of the guide catheter is established in a substantially contiguous manner against the aortic wall for a substantial length (at least about 1.5 centimeters). Moreover, a distal end of this contact portion is positioned against the aortic wall substantially directly opposite the ostium of the left main coronary artery. This provides a point of support for the guide catheter that directly opposes stenotic pushback forces directed outwardly from the ostium of the left main coronary artery. In addition, a distal tip portion of the guide catheters of the present invention (including the third and fourth straight portions) when disposed in the aortic complex provide a generally rectilinear axis of support that extends substantially across the ascending aorta from the distal end of the contact portion to the ostium of the left main coronary artery. This axis of support substantially directly opposes the axis of the stenotic push back forces thereby substantially diminishing the potential for prolapse of the distal tip portion of the guide catheters of the present invention.
This advantageous orientation of the guide catheters of the present invention (when in the aortic complex) result directly from the configuration of the guide catheters when in a relaxed state prior to insertion in the cardiovascular system. Foremost, the guide catheters of the present invention have a transition portion including the tertiary curve portion and the second straight portion positioned between the first straight portion and the secondary curve portion. The transition portion forms an obtuse angle of between 130xc2x0 to 150xc2x0. This transition portion causes the second straight portion and a proximal portion of the secondary curve portion to form the contact portion (in use) that rests substantially contiguous against the wall of the ascending aorta. The presence of the transition portion causes the second straight portion to rest naturally against the ascending aortic wall thereby allowing the primary point of backup support (at a distal end of the area of support, i.e., a distal end of the contact portion) to be positioned very low in the ascending aorta as compared to the single point of backup support for a Judkins-style catheter. The primary point of backup support for the guide catheters of the present invention is a point along the ascending aortic wall substantially directly opposite the ostium of the left main coronary artery. Moreover, because the second straight portion of the guide catheter of the present invention rests naturally against the ascending aortic wall, a large area of general backup support (the substantially contiguous contact portion) is provided for the guide catheter which makes it quite difficult to dislodge the guide catheter from its desired orientation.
In addition, the presence of the tertiary curve portion provides more bends in the guide catheter (than a Judkins-style guide catheter) when disposed in the aortic complex thereby making each bend in the catheter a milder angle to allow a fuller transmission of distal pushing forces through the guide catheter. Moreover, the mild obtuse angle (about 160xc2x0) of the primary curve portion of the guide catheter and the long fourth straight portion (at least about equal to or longer than the third straight portion) cause the distal tip portion to align substantially coaxially within the ostium of the left main coronary artery. The length of the fourth straight portion causes the primary curve portion to be positioned within the ascending aorta, i.e., outside the ostium of the left main coronary artery.
All of these advantages of the guide catheter of the present invention are gained by redesigning the basic configuration of the guide catheter (in its relaxed state). Accordingly, when the guide catheter of the present invention is fully disposed in the aortic complex, a substantially different and superior (i.e., better) orientation is achieved over the previous prior art catheters (e.g. Judkins-style). Moreover, these advantages are achieved without adding additional structure (xe2x80x9clockingxe2x80x9d mechanism, support flaps, xe2x80x9cbracingxe2x80x9d means, and the like) to the distal end portion of the guide catheter. For example, the guide catheter of the present invention has means for stabilizing (supporting) the guide catheter against (or relative to) the wall of the ascending aorta such that the guide catheter is supported by the ascending aortic wall at a point substantially directly opposite the ostium of the left main coronary artery. Moreover, the means for stabilizing is the contact portion of the guide catheter defined by the second straight portion and the proximal portion of the secondary curve portion. Accordingly, unlike the prior art (e.g. Shiu), the stabilizing means of the guide catheter of the present invention is defined or formed by an outer portion (or surface) of the wall of the tubular member that comprises the guide catheter. The guide catheter of the present invention lacks the complex and bulky structure of the previous prior art catheters that attempted to modify the Judkins-style catheter. Instead, the guide catheter of the present invention provides superior performance by making a fundamental change in the overall shape of guide catheters for the left main coronary artery.